DETERMINATION OF TRAVELTIME IN THE DELAWARE RIVER, HANCOCK, NEW YORK, TO THE DELAWARE WATER GAP BY USE OF A CONSERVATIVE DYE TRACER by Kirk E. White and Todd W. Kratzer______
U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 93-4203
Prepared in cooperation with the DELAWARE RIVER BASIN COMMISSION
Lemoyne, Pennsylvania 1994 U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBIT, Secretary
U.S. GEOLOGICAL SURVEY
Robert M. Hirsh, Acting Director
For additional information Copies of this report may be write to: purchased from:
U.S. Geological Survey Earth Science Information Center District Chief Open-File Reports Section U.S. Geological Survey Box 25286, MS 517 840 Market Street Denver Federal Center Lemoyne, Pennsylvania 17043-1586 Denver, Colorado 80225 CONTENTS Page
Abstract...... 1 Introduction ...... 1 Purpose and scope...... 1 Acknowledgments...... 4 Description of study reach ...... 5 Methods of data collection and analysis ...... 5 Field and laboratory procedures...... 5 Data analysis ...... 8 River discharge...... 16 Traveltime...... 23 Measured...... 23 Predicted...... 52 Summary...... 53 References cited ...... 54
ILLUSTRATIONS
Figure 1. Location of injection sites, sampling sites, and streamflow-measurement stations on the Delaware River, Hancock, N.Y., to the Delaware Water Gap...... 3 2-5. Graphs showing: 2. Smoothing of time-concentration curve irregularities for a hypothetical data set...... 8 3. Extrapolation of data at the leading and trailing edges of the time-concentration curve for a hypothetical data set...... 10 4. Interpolation of data at the trailing edge of the time-concentration curve for a hypothetical data set...... 11 5. Separation of time-concentration curve for the Eshback Access and Port Jervis dye injection, May 6,1991...... :...... 15 6-10. Hydrographs showing: 6. Discharge of Delaware River at Callicoon, N.Y., May 8-9 and August 12-15,1991. ... 17 7. Discharge of Delaware River above Lackawaxen River near Barryville, N.Y., May 8-9 and August 12-15,1991...... 18 8. Discharge of Delaware River at Port Jervis, N.Y., May 6-7 and August 5-7,1991. .... 19 9. Discharge of Delaware River at Montague, N.J., May 6-7 and August 5-7,1991...... 20 10. Discharge of Delaware River below Tocks Island Damsite, near Delaware Water Gap, Pa., May 6-7 and August 6-7,1991...... 21 11. Graph showing relation between discharge and flow duration at index streamflow- measurement stations on the Delaware River ...... 22 12. Graphs showing observed time-concentration curves from the May 1991 medium- flow study for: 12A. Subreach 1 and subreach 2A ...... 24 12B. Subreach 2B and subreach 3...... 25 12C. Subreach 4A and subreach 4B...... 26 ILLUSTRATIONS-Continued Page
Figure 13. Graphs showing observed time-concentration curves from the August 1991 low-flow study for: 13A. Subreach 1 and subreach 2A ...... 27 13B. Subreach 2B and subreach 3...... 28 13C Subreach 4A and subreach 4B...... 29 14. Graphs showing cumulated traveltime for May and August 1991 medium- and low- flow dye injections, Delaware River, Hancock, N.Y., to the Delaware Water Gap...... 30 15. Graph showing dye-cloud velocity as a function of average discharges at streamflow- measurement stations Delaware River at Callicoon, N.Y., and above Lackawaxen near Barryville, N.Y...... 33 16. Graphs showing relation of traveltime and distance of leading edge of dye cloud at selected flow durations on the Delaware River for: 16A. Sampling sites 1-6, Hancock, N.Y., to 0.1 mile downstream of Tenmile River confluence...... 38 16B. Sampling sites 6-15,0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap...... 39 17. Graphs showing relation of traveltime and distance of peak concentration of dye cloud at selected flow durations on the Delaware River for: 17A. Sampling sites 1-6, Hancock, N.Y, to 0.1 mile downstream of Tenmile River confluence...... 40 17B. Sampling sites 6-15,0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap...... 41 18. Graphs showing relation of traveltime and distance of trailing edge of dye cloud at selected flow durations on the Delaware River for: ISA. Sampling sites 1-6, Hancock, N.Y, to 0.1 mile downstream of Tenmile River confluence...... 42 18B. Sampling sites 6-15,0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap...... 43 19. Graphs showing relation between dye cloud duration and distance at selected flow durations on the Delaware River for: 19A. Sampling sites 1-6, Hancock, N.Y, to 0.1 mile downstream of Tenmile River confluence...... 45 19B. Sampling sites 6-15,0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap...... 46 20. Graph showing time-concentration curves for the Delaware River at Narrowsburg pool, May 1,1991 ...... 48 21-23. Graphs comparing: 21. Time-concentration curves from Kellam's Bridge for the low-flow and surge-wave studies on the Delaware River...... 49 22. Time-concentration curves from Pond Eddy for the low-flow and surge-wave studies on the Delaware River...... 50 23. Time-concentration curves from iv TABLES Page Table 1. River mileage for bridge crossings, U.S. Geological Survey streamflow-measurement stations, dye study locations, and selected tributaries on the Delaware River, Hancock, N.Y., to the Delaware Water Gap ...... 6 2. River mileage, river segment length, and drainage areas for sampling sites on the Delaware River, Hancock, N.Y., to the Delaware Water Gap...... 7 3. Time-concentration curve peak concentrations, areas, and centroids for the May medium-flow study on the Delaware River, Hancock, N.Y., to the Delaware Water Gap...... 12 4. Time-concentration curve peak concentrations, areas, and centroids for the August low-flow study on the Delaware River, Hancock, N.Y., to the Delaware Water Gap...... 13 5. Time-concentration curve peak concentrations, areas, and centroids for the August surge-wave studies on the Delaware River ...... 14 6. Traveltimes for the May medium-flow dye study, Delaware River, Hancock, N.Y., to the Delaware Water Gap...... 31 7. Traveltimes for the August low-flow dye study, Delaware River, Hancock, N.Y, to the Delaware Water Gap ...... 32 8. Dye-cloud velocities and representative stream discharges for leading edge, peak, and trailing edge of dye cloud for reach of the Delaware River between Cochecton, N.Y., and Narrowsburg, N.Y...... 32 9. Dye-cloud velocities at discharges corresponding to various flow durations at Delaware River at Callicoon, N.Y., and Delaware River above Lackawaxen River near Barryville, N.Y...... 34 10. Traveltimes for leading edge of dye cloud at selected flow durations on the Delaware Rive^ Hancock, N.Y. to the Delaware Water Gap ...... 35 11. Traveltimes for peak concentration of dye cloud at selected flow durations on the Delaware River, Hancock, N.Y, to the Delaware Water Gap...... 36 12. Traveltimes for trailing edge of dye cloud at selected flow durations on the Delaware River, Hancock, N.Y, to the Delaware Water Gap...... 37 13. Time durations for dye cloud at selected flow durations on the Delaware River, Hancock, N.Y, to the Delaware Water Gap ...... 44 14. Traveltimes, areas, and centroids of the dye cloud for the Delaware River at Narrowsburg pool study, May 1,1991 ...... 47 15. Dye-cloud velocities and durations for the Delaware River at Narrowsburg pool study, May 1,1991 ...... 47 CONVERSION FACTORS AND ABBREVIATIONS Multiply By To Obtain foot (ft) 0.3048 meter mile (mi) 1.609 kilometer square mile (mi2) 2.590 square kilometer foot per mile (ft/mi) 0.1894 meter per kilometer pound (Ib) 453.6 gram foot per second (ft/s) 0.3048 meter per second cubic foot per second (ft3/s) 0.02832 cubic meter per second mile per hour (mi/h) 1.609 kilometer per hour Temperature °C=5/9 (°P-32) Abbreviated water-quality units used in report: micrograms per liter (|lg/L) VI DETERMINATION OF TRAVELTIME IN THE DELAWARE RIVER, HANCOCK, NEW YORK, TO THE DELAWARE WATER GAP BY USE OF A CONSERVATIVE DYE TRACER by Kirk E. White1 and Todd W. Kratzer2 ABSTRACT Traveltime of a soluble substance was determined for a 120-mile reach of the Delaware River from the confluence of the East Branch Delaware River and the West Branch Delaware River at Hancock, N.Y, to the Delaware Water Gap. Dye studies were conducted at the 85-95 percent and 25-30 percent flow durations. Discharges ranged from 500-1,740 cubic feet per second during the 85-95 percent flow duration and 3,070-7,500 cubic feet per second for the 25-30 percent flow duration. The data were used to develop a set of time-concentration curves that would enable estimation of the traveltime of a spill at any point in the river within the study reach for 10 flow durations. The leading edge of a contaminant spill at Buckingham Access would take about 70 hours to reach the Delaware Water Gap when flows are at the 30-percent flow duration. The trailing edge (location of the dye cloud when concentrations would decrease to 10 percent of the peak concentration) would take about 50 hours after the arrival of the leading edge. INTRODUCTION Resource managers and health agencies need traveltime information on rivers at various flows to respond effectively in the event of a toxic spill into the river. Traveltime information also is valuable in the calibration of the hydrodynamics for toxic spill and water-quality models. In 1990, the Delaware River Basin Commission (DRBC) proposed a study to determine the traveltime characteristics of a 120-mi reach of the upper Delaware River (fig. 1) from Hancock, N.Y., to the Delaware Water Gap. The study was done as a cooperative effort by the U.S. Geological Survey (USGS) and the DRBC; substantial support was provided by the National Park Service and the Upper Delaware Council. Purpose and Scope This report describes the movement of a conservative soluble substance in the upper Delaware River and presents methods of estimating traveltimes in the event of a spill or discharge of a soluble contaminant at various locations in the study reach. On May 1,1991, rhodamine WT, 20-percent dye was injected into the Delaware River near river mile 295. The resulting dye cloud was sampled 5 mi downstream at Narrowsburg, N.Y. A dye study was conducted May 6-9 at a medium-flow regime (3,070 to 7,500 ft3/s) on a 120-mi reach of the Delaware River between Hancock, N.Y., and the Delaware Water Gap. Dye studies were conducted at low-flow regimes (500 to 1,740 ft3/s) August 5-7 and August 12-15 on the reaches from the mouth of the Lackawaxen River to the Delaware Water Gap and from Hancock, N.Y, to Barryville, N.Y, respectively. On August 7-8 and 14-15, dye was injected into the Delaware River at three locations. The resulting dye clouds were sampled while surge waves, created by reservoir releases, passed through them. 1 K.E. White, Hydrologist, U.S. Geological Survey. 2 T.W. Kratzer, Water Resources Engineer, Delaware River Basin Commission. 75° 15' 74°45' yino/VY nLW ' URIX ^^> *ffc^UV »^^mmm^mmt^mmmm^mm^^ - 42°00' _SUBREACH2A _ _ _ _ 41°30' 41°30' - UDSRR Southern Terminus _ _01434000, " iMalomor / _ _ - Milford MDSRR ----/--- / OH38500 Northern Termin EXPLANATION STREAMFLOW-MEASUREMENT STATION SAMPLING SITE STREAMFLOW-MEASUREMENT AND SAMPLING SITE UPPER DELAWARE SCENIC AND RECREATIONAL RIVER MIDDLE DELAWARE SCENIC AND 41°00' 41°00' - RECREATIONAL RIVER 0 2 4 6 8 10 MILES I [£ _ Spmhem Jerminus_ _ _/ Figure 1. Location of injection sites, sampling sites, and streamflow-measurement stations on the Delaware River, Hancock, N.Y., to the Delaware Water Gap. Acknowledgments This study was conducted with the cooperation of many Federal, State, and private agencies and volunteers. The authors would like to thank the participating agencies for their support during this study. Special thanks are extended to the individuals who provided logistical assistance and collected and analyzed the data used in this report. The cooperation of Orange and Rockland Power Company, Pennsylvania Power and Light Company, and New York City Department of Environmental Protection Bureau of Water Supply, whose assistance was essential in providing and maintaining the desired flows during the dye studies, is greatly appreciated. The following is a list of individuals who provided assistance with this study: National Park Service, Delaware Water Gap National Recreational Area Ramona Abraham Deborah Drelich Karl Klein Victor Perez Dirk Amtower Carol Hansen Karen Messaros Suellyn Shupe Gary Breon Keith High Wayne Millington Karl Thuene Michael Croll Elizabeth Johnson George Pearlingi Michael Zirwas Marion Damiano-Nittoli National Park Service, Upper Delaware Scenic And Recreational River William Bortree Carla Hahn Vince Pareago Vicki Snitsler-Neeck Diane Christman-Hinz Ruth Hartmann Barbara Perry Kevin Snyder Craig Clapper Albert Henry Angel Pino Sandra Speers-Schultz Gary Cochraine Leonard Hoffert Robert Price Brian Stackowicz Clifford Daniels Ralph Huebner Deborah Qualey Patricha Stiner Jeffrey Donahue Thomas Jeffers Kevin Rcish Jacquie Tinker Christine Fraser Michael Klingensmith Michael Reubner Dana Valensky Jean Gabert JoAnne Merritt James Robish Glenn Voss Wanda Goodwin Rhonda Moore Malcolm Ross, Jr. William Weber Milton Groesbeck Larry Neal, Jr. Donald Sledz Robert Wicksnes Upper Delaware Council William Douglass Janice Fischer Kathy Johnson David Soote ______Delaware River Basin Commission______Richard Albert Warren Huff Christian Mainelli Darryl Rulon Robert Everest Robert Limbeck Donald Miller Ronald Rulon Cynthia Faunce Bruce Laughlin Christopher Roberts Paul Scally Richard Fromuth Tim Lazaro U.S. Environmental Protection Agency, Region III ______Pennsylvania Fish Commission Charles Kanetsky Margaret Passmore David Spots Leroy Young ______City of New York______Rutgers University___ Raphael Hurowitz Stephen Shindler Yun-Tai-Wu Bin Qiu Monroe County Planning Commission Sebastian Degregorio Lisa Surma Pike County Conservation District Susan Beecher Jeffrey Carter Hannelore Schanzenbacher Citizen Volunteers Jennifer Barry Gerry Howson Peter Pietraszak Henry Snyder Ruth Burrkle William Kratzer Leland Pollock Thomas Van Orden William Cutler Mary Ellen Noble Cynthia Poten Edward Wesley Frank Hartman Leonard Peck Roberta Rodimer Barbara Yeaman Charles Howson Description of Study Reach The study reach (fig. 1) is approximately 120 mi long and extends from just downstream of the confluence of the East Branch Delaware River and the West Branch Delaware River at Hancock, N.Y., to the Delaware Water Gap. The study reach includes the Upper and Middle Delaware Rivers. In this reach, the river flows southeast until reaching Port Jervis where it changes direction and flows southwest to the Delaware Water Gap. The largest tributaries to the Delaware River in this section are the Lackawaxen River, which has a drainage area of 597 mi2; the Neversink River, which has a drainage area of 349 mi2; and Brodhead Creek, which has a drainage area of 287 mi2. The Delaware River in the study reach is a series of alternating pools and riffles with several major rapids. The average slope over the entire reach is approximately 5.5 ft/mi. Large eddies throughout the study reach affect traveltime. Depths in the study reach range from several feet at low flow to about 110 ft at Narrowsburg (river mile 290). River mileage used in this report was determined by the DRBC (1988) and is the number of miles upstream from the Atlantic Ocean-Delaware Bay interface. Table 1 lists landmarks in the study reach and their river miles. All of these landmarks are on USGS 7 1/2-minute topographic maps, but not all are shown on figure 1. A number of reservoirs regulate the flow of the river in the study reach. Cannonsville Reservoir is on the West Branch of the Delaware River; Pepacton Reservoir is on the East Branch of the Delaware River; and Neversink Reservoir is on the Neversink River, the latter entering the main stem of the Delaware River just below Port Jervis at river mile 254. These reservoirs are operated by New York City. Lake Wallenpaupack, operated by Pennsylvania Power and Light Company, is on Wilson Creek, a tributary to the Lackawaxen River. The Mongaup Reservoir system, consisting of three reservoirs operated by Orange and Rockland Power Company, is on the Mongaup River. During low-flow periods, reservoir releases often make up a majority of the river flow. All reservoir releases are coordinated with the Delaware River Master to insure that flow does not fall below criteria established by the U.S. Supreme Court or the DRBC. Methods of Data Collection and Analysis Measurements of traveltime of a dye tracer are used to define the movement of a solute in a river. Standard sampling procedures (Hubbard and others, 1982; Kilpatrick and Wilson, 1989) and fluorometric procedures (Wilson arid others, 1984) are well documented. In general, the described standard procedures were followed during this study. One exception was the use of a specific gravity value of 1.10 for the dye, as determined by hydrometer, to calculate concentrations of the calibration standards. Field and Laboratory Procedures A preliminary dye study was conducted for a short, isolated reach of the river at Narrowsburg, N.Y., to determine the effect that a deep pool and associated eddy would have on traveltime. Concern that dye would not exit the Narrowsburg pool in measurable concentrations led to the division of subreach 2, which contains the pool, into subreach 2A and 2B. During the May study, the threat of severe thunderstorms and tornadoes after injection prompted a split in subreach 4, the most downstream subreach, into subreach 4A and 4B and an additional dye injection. The additional dye injection was performed to expedite sampling at the downstream sites. The 120-mi reach was divided into a total of 6 subreaches (1,2A, 2B, 3,4A, 4B) containing 15 stream segments for both the May and August 1991 study. A subreach is characterized by a dye injection site with three to four downstream sampling points. The 15 sampling sites that define the segments are shown on figure 1 and are numbered in ascending order in the downstream direction. Table 2 gives the sampling site name, river mileage, river segment length between sampling sites, and drainage areas. The Dingmans sampling locations for the medium- and low-flow studies were about 0.5 mi apart. Dingmans is shown as a single point on figure 1, but both locations are listed in table 2. Table 1. River mileage for bridge crossings, U.S. Geological Survey streamflow-measurement stations, dye stuay locations, and selected tributaries on the Delaware River, Hancock, N. Y., to the Delaware Water Gap Dye sampling Delaware Location site no. River mile1 East and West Branch Delaware River confluence 330.70 Subreach 1 and Cannonsville Reservoir surge-wave dye injections 330.50 Buckingham Access 325.14 Lordville Bridge 321.60 Kellam's Bridge 312.59 Callicoon Bridge 303.70 Callicoon Creek confluence 303.62 Subreach 2A dye injection 303.61 USGS streamflow-measurement station at Callicoon, N.Y. 303.20 Cochecton Bridge 298.40 Skinners Falls Bridge 295.40 Just downstream from Skinners Falls Bridge (Narrowsburg Pool dye injection) 295.33 Narrowsburg (N.Y. Access) 290.34 Narrowsburg Bridge (US Rt. 106) 289.90 Narrowsburg (Pa. Access) Subreach 2B dye injection 289.43 Erie Railroad Bridge 285.20 Tenmile River confluence 284.27 Just downstream from Tenmile River confluence 284.15 USGS streamflow measurement station upstream from Lackawaxen River confluence 279.70 Just upstream from Lacka waxen River confluence 277.81 Lacka waxen River confluence 277.65 Subreach 3 dye injection 277.49 Lacka waxen Bridge 277.40 Lake Wallenpaupack surge-wave dye injection 275.50 Barryville Bridge 273.50 Pond Eddy Bridge 265.50 Mongaup River confluence 261.10 Erie Railroad Bridge 258.40 Rio Reservoir surge-wave dye injection 257.05 Port Jervis Bridge (US Rt. 209) 10 254.75 Subreach 4A dye injection and USGS streamflow-measurement station at Port Jervis, N.Y. 254.73 US Route 84 Bridge 253.65 Neversink River confluence 253.64 Milford Beach and USGS streamflow-measurement station at Montague, N.J. 11 246.31 Milford Bridge (US Rt. 206) 246.00 Just upstream from Dingmans Creek confluence (medium-flow sampling location) 12A 239.24 Dingmans Creek confluence 239.20 Just upstream from Dingmans Ferry Toll Bridge (low-flow sampling location) 12B 238.73 Dingmans Ferry Toll Bridge 238.70 Eshback Access (Subreach 4B dye injection) 231.97 Bushkill Access 13 228.11 Bushkill Creek confluence 226.90 Smithfield Beach 14 218.34 USGS streamflow-measurement station near Delaware Water Gap, Pa. 216.10 Brodhead Creek confluence 213.00 Delaware Water Gap Toll Bridge (US Rt. 80) 212.10 Kittatinny Access 211.50 Just downstream from Kittatinny Access ______15 211.37 River mile zero is located at the mouth of the Delaware Bay. Table 2. River mileage, river segment length, and drainage areas for sampling sites on the Delaware River, Hancock, N.Y., to the Delaware Water Gap [mi2, square mile] Segment Drainage Location Site no. River mile length area (miles) (mi2) Upstream study boundary Injection 330.50 0.00 1,506 Buckingham Access 1 325.14 5.36 1,524 Kellam's Bridge 2 312.59 12.55 1,667 Cochecton Bridge 3 298.40 14.19 1,834 Narrowsburg (N.Y. access) 4 290.34 8.06 1,909 Narrowsburg (Pa. access) 5 289.43 .91 1,911 Just downstream from Tenmile River confluence 6 284.15 5.28 1,975 ' Just upstream from Lackawaxen River confluence 7 277.81 6.34 2,029 Barryville Bridge 8 273.50 4.31 2,659 Pond Eddy Bridge 9 265.50 8.00 2,820 Port Jervis Bridge (US Rt. 209) 10 254.75 10.75 3,070 Milford Beach 11 246.31 8.44 3,480 Dingmans Medium-flow sampling location 12A 239.24 7.07 3,520 Low-flow sampling location 12B 238.73 7.58 3,540 Bushkill Access 13 228.11 3,615 Medium-flow 11.13 Low-flow 10.62 Smithfield Beach 14 218.34 9.77 3,850 Just downstream from Kittatinny Access 15 211.37 6.97 4,167 At each injection site, rhodamine WT, 20-percent dye was injected at a continuous rate from a boat as it traversed the river. Each injection was well upstream from the computed distance required for 95- percent mixing at the first sampling site in each subreach (Kilpatrick and Wilson, 1989). Dye injection crews and equipment were segregated from sampling crews to avoid sample contamination. The first two sampling sites downstream from each injection site were sampled at three transect points (left, right, and mid-channel), to determine if complete mixing had occurred. All stream samples were analyzed in the field by use of a fluorometer to determine the arrival of the dye cloud and the position on the time-concentration curve, and to adjust the sampling frequency. Immediately following the low-flow studies that took place in August, three short reaches were sampled during typical releases from Cannonsville Reservoir, Lake Wallenpaupack, and the Mongaup System reservoirs. Data were collected from two sampling sites per release as the surge wave passed through the dye cloud. The surge-wave data were compared to the data collected from those same sampling sites during the preceding low-flow study to observe the relative effect of a flood wave on traveltime and dispersion. All samples collected during the study were analyzed in the laboratory on the same fluorometer. Sample temperatures, determined during analysis, varied over a range of several degrees. The fluorometer was calibrated with standard solutions prepared from the same dye lot used in the study. The fluorescence values of all samples were adjusted by use of a temperature-correction curve to compensate for the effect of temperature on fluorescence. Data Analysis Following laboratory analysis of all dye samples, concentrations and traveltimes were entered into computer files for data analysis. Time-concentration curves3 were analyzed for continuity, area under the curve, and centroids. Continuity includes the curve "smoothness" and the completeness of the leading and trailing edges of each time-concentration curve. During the medium-flow study, dye clouds overlapped and were separated by use of regression and extrapolation techniques. Dye-cloud data periodically showed irregularities in the time-concentration curve profile caused mainly by channel nonuniformity. Other causes may include instrument and human error. These curves were smoothed for area and centroid analysis by visually inspecting the curve for the best-fit upward or downward tendency and adjusting the data accordingly. Figure 2 illustrates this method on a curve created from a hypothetical data set. __ OBSERVED CONCENTRATION Ul Q...... INTERPOLATED CONCENTRATION CO 1 O o a: o ^ 5 U 2 O O O 1 0123456789 10 12 TIME SINCE INJECTION, IN HOURS Figure 2. Smoothing of time-concentration curve irregularities for a hypothetical data set. 3 Time-concentration curve is used in place of "dye-cloud" when referring to a longitudinal profile of the three dimensional dye- cloud mass. When time-concentration data were incomplete for the trailing or leading edge, extrapolation or interpolation was used to construct these curve components. A least-squares statistical estimate was performed on the last three to five data points to determine coefficients for the regression equation Y = mX+b, (1) where Y is concentration, m is slope of the regression line, X is time since injection, and b is Y-intercept of the regression line. In equation 1, where x,- is individual X values, i/^is individual Y values, x is average of X values, and y is average of Y values. The Y-intercept (b) is determined with the following equation: b = y-mx (3) If data were missing at the leading or trailing edges of the time-concentration curve and no curvilinear trend was evident, the existing data were linearly extrapolated to no lower than 0.2 |ig/L and exponentially extrapolated to 0.01 ng/L for the leading edge and to 1 percent of the peak concentration for the trailing edge. If a curvilinear trend was evident, exponential extrapolation was used to construct the leading edge or trailing edge of the curve. Figures 3 and 4 illustrate the methods of extrapolation and interpolation, respectively, on curves created from hypothetical data sets. When data voids existed prior to the extreme points of the time-concentration curve, exponential interpolation was used to construct that part of the curve (fig. 4). Exponential extrapolation and interpolation methods use logarithmic values for *,- and y,- in equation 2. Area under each time-concentration curve was computed to determine the approximate location of "complete mix" and to determine longitudinal dye losses. Complete mix is defined as a homogenous concentration existing both vertically and laterally within a channel cross section and is represented as cross-sectional concentrations not exceeding ±10 percent of the cross-sectional average. Dye losses occur from dye adsorption onto channel substrates including sediment, aquatic plants, and debris and from retainment in eddy zones. Many of these losses are temporary as dye is slowly resupplied to the water column. Nonuniform mixing of dye across a transect presents conditions that seem to indicate a loss or gain of dye mass when these data are compared to the data collected at the next upstream site. However, no change in dye mass has actually occurred. Tables 3, 4, and 5 present the time-concentration curve peak concentrations, areas, and centroids for the medium-flow, low-flow, and surge-wave studies, respectively. Although dye was injected laterally across the river, nonuniform flow velocities across the transect moved the dye downstream at different rates. This created a line of dye in the river channel that was spreading longitudinally (upstream and downstream) as well as laterally (side to side). Lateral spread continued from 15 to more than 18 mi downstream of the injection site during the medium-flow study and g 7 OBSERVED CONCENTRATION , EXTRAPOLATED CONCENTRATION O o o: O Q 4 L_ O z O 3 a 2 o o 45678 10 12 TIME SINCE INJECTION, IN HOURS Figure 3. Extrapolation of data at the leading and trailing edges of the time-concentration curve for a hypothetical data set. from 6 to more than 14 mi downstream for the low-flow study. Prior studies (Fischer and others, 1979) have shown that vertical mixing occurs nearly instantly in relatively shallow waterways such as the Delaware River. The Narrowsburg pool, where depths exceed 100 ft, is one possible exception. The centroid (or center of gravity) of each dye cloud was computed and used as another indicator of complete mix in transects with more than one sampling site. Centroid data are presented in tables 3,4, and 5 for the medium-flow, low-flow, and surge-wave studies, respectively. Time-averaged concentrations (vertical centroid coordinates) were compared across those transects with more than one sampling site. Time-averaged concentrations approaching unity throughout a cross-section indicate a more even spread approaching complete mix. During the medium-flow study in May, the injection at Eshback Access, for subreach 4B, was added to provide a supplemental, faster moving dye cloud from the injection site to Kittatinny Access (site 15). Preliminary dye-cloud velocity estimates showed that sampling crews at the Kittatinny Access would be able to cease sampling approximately 10 hours sooner than originally scheduled for the Port Jervis injection. Unfortunately, data collected at the first site downstream (Bushkill Access, site 13) of the Eshback Access injection showed that the Port Jervis injection-site dye cloud was farther downstream than anticipated, and dye-cloud overlapping had begun. The overlapping continued as the clouds moved downstream. Data collected at the most downstream site (Kittatinny Access) showed that the two clouds had merged into a single cloud. 10 a: __ OBSERVED CONCENTRATION ...... INTERPOLATED CONCENTRATION io a:o o 9 3 15 £ o5 2 z o o 45678 10 12 TIME SINCE INJECTION, IN HOURS Figure 4. Interpolation of data at the trailing edge of the time-concentration curve for a hypothetical data set. Data for each time-concentration curve were separated by use of an extrapolation technique that utilized the linearity of dye-cloud spread between the upstream sites and extrapolated the linear spread to the downstream sites. Linearity of dye-cloud spread within this reach of the Delaware River was supported by both the medium-flow and low-flow studies. Time-concentration curves of the three upstream sites, Milford Beach (site 11), just upstream from Dingmans Creek (site 12A), and Bushkill Access (site 13), were separated into percentages of the peak concentrations in combination with the associated traveltimes. Concentration increments of 10 percent (such as 10, 20, and 30 percent) of the peak concentration were determined for the leading and trailing edge of each time-concentration curve and matched to the respective traveltime. These traveltimes were regressed (equations 1-3) against river miles. Peak concentrations were regressed (equations 1-3) with the reciprocal of the square root of the travel times (l/VTp). This method was illustrated by Thomann and Mueller (1987). The resultant regression equations were then used to extrapolate the traveltimes and associated concentrations to the downstream sites. All of the regression analyses showed correlation coefficients greater than 0.97; most were greater than 0.99. A correlation coefficient of 1 or -1 signifies a perfect relation between the compared variables. The extrapolated time-concentration curve area was subtracted from the observed area to define the remaining (extracted) area. The remaining area and its characteristics represented the dye cloud from the Eshback Access injection. Figure 5 shows the overlap and separations of the Kittatinny Access time- concentration curves. 11 Table 3. Time-concentration curve peak concentrations, areas, and centroids for the May medium-flow study on the Delaware River, Hancock, N. Y., to the Delaware Water Gap [u,g/L, microgram per liter; hr, hour] Time-concentration-curve centroid Area under Time- Peak Average peak Average Site Transect Average concentration concentration time-concen time-concen Time since averaged concen number location tration curve tration area injection concen (H9/L) (MO/L) tration (H9/L) x hr (jig/L) x hr (hr) tration (W>L) (MJ/L) Subreach 1 - Injected 10.31 liters of rhodamine WT, 20-percent dye at 1000 on May 8, 1991, at river mile 330.50 1 Left 10.10 9.31 4.05 2.57 Middle1 14.18 9.23 3.65 4.25 Right 11.05 11.78 9.94 9.49 3.99 3.36 3.39 2 Left 3.19 8.23 13.18 1.03 Middle1 3.17 8.38 13.36 1.03 Right 2.52 2.96 8.26 8.29 13.94 .86 .97 3 Middle 1.73 7.51 22.77 .60 Subreach 2A - Injected 33.24 liters of rhodamine WT, 20-percent dye at 0800 on May 8,1991, at river mile 303.61 3 Left 29.11 24.83 3.77 7.80 Middle1 38.19 21.89 3.41 10.60 Right 27.44 31.58 17.43 21.38 3.52 7.45 8.62 4 Left 10.74 25.08 8.70 3.57 Middle1 13.04 24.20 8.24 4.04 Right 12.83 12.20 21.73 23.67 8.31 3.75 3.79 5 Middle 5.73 22.35 11.18 1.70 6 Middle 5.11 25.34 14.73 1.54 Subreach 2B - Injected 8.00 liters of rhodamine WT, 20-percent dye at 0500 on May 8,1991, at river mile 289.43 6 Left 2.14 4.24 5.50 .56 Middle1 7.51 5.05 3.59 1.72 Right 4.01 4.55 2.83 4.04 3.47 .98 1.09 7 Middle 3.54 4.51 7.54 .94 8 Middle 1.93 3.53 10.40 .59 Subreach 3 - Injected 30.93 liters of rhodamine WT, 20-percent dye at 0910 on May 6,1991, at river mile 277.49 8 Left 14.81 13.11 3.20 4.30 Middle1 30.99 14.78 2.87 8.44 Right 21.70 22.50 18.97 15.62 3.23 5.85 6.20 9 Left 5.00 14.64 9.45 1.65 Middle 6.64 15.05 8.85 2.08 Right1 6.74 6.13 14.66 14.78 8.89 2.14 1.96 10 Right 4.19 13.89 14.70 1.43 11 Middle 2.48 11.06 20.40 .85 Subreach 4A - Injected 51.55 liters of rhodamine WT, 20-percent dye at 0525 on May 6,1991, at river mile 254.73 11 Left1 18.05 22.14 5.37 5.43 Middle 17.60 21.83 5.36 5.33 Right 11.70 15.78 18.97 20.98 5.95 3.42 4.73 12 Left 7.43 21.73 12.78 2.17 Middle 7.77 22.41 12.14 2.56 Right1 8.31 7.84 22.71 22.28 12.17 2.49 2.41 13 Middle 4.20 19.89 20.07 1.37 14 Middle 2.77 18.41 28.18 .89 15 Middle 1.85 14.28 33.74 .60 Subreach 4B - Injected 20.62 liters of rhodamine WT, 20-percent dye at 1800 on May 6,1991, at river mile 231.97 13 Middle 8.34 8.51 15.51 2.44 14 Middle 2.20 6.36 23.06 .72 15 Middle____1.34______5.81______28.98_____.42______1 Site selected for traveltime analyses. 12 Table 4. Time-concentration curve peak concentratbns, areas, and centroids for the August low-flow study on the Delaware River, Hancock, N.Y., to the Delaware Water Gap [u,g/L, microgram per liter; hr, hour] Time-concentration-curve centroid Area under Average Time- Peak Average peak Average Site Transect time-concen time-concen Time since average concentration concentration concen number location tration curve tration area injection concen (Mfl'L) 0*0/L) tration (W/L)*hr (Hg/L)*hr (hr) tration (W/L) (MO/L) Subreach 1 - Injected 6.001iters of rhodamine WT, 20-percent dye at 0900 on August 12,1991, at river mile 330.50 1 Left 7.77 20.45 9.24 2.36 Middle1 8.14 20.40 9.32 2.36 Right 7.73 7.88 26.61 22.49 10.31 2.28 2.33 2 Left 1.93 20.28 36.40 .65 Middle1 2.00 21.15 36.23 .66 Right 1.72 1.88 20.40 20.61 38.83 .56 .62 3 Middle 1.09 15.68 62.22 .41 Subreach 2A - Injected 16.50 liters of rhodamine WT, 20-percent dye at 0655 on August 12,1991, at river mile 303.61 3 Left 13.00 50.23 11.04 3.88 Middle 15.10 51.15 10.08 4.69 Right1 15.10 14.40 58.24 53.21 10.43 4.61 4.39 4 Left 6.70 53.55 24.77 2.18 Middle1 7.38 53.64 22.93 2.42 Right 6.68 6.92 54.69 53.96 24.89 1.90 2.17 5 Middle 3.66 51.37 33.17 1.03 6 Middle 2.90 51.66 43.20 .89 Subreach 2B - Injected 5.50 liters of rhodamine WT, 20-percent dye at 0500 on August 12,1991, at river mile 289.43 6 Left 2.39 12.02 12.85 .60 Middle 4.69 11.77 8.63 1.26 Right1 5.65 4.24 17.13 13.64 9.17 1.44 1.10 7 Left 2.22 16.65 22.12 .70 Middle1 2.30 16.82 22.22 .72 Right 2.24 2.25 17.34 16.94 23.22 .72 .71 8 Middle 1.11 11.47 30.54 .42 Subreach 3 - Injected 11,81 liters of rhodamine WT, 20-percent dye at 0900 on August 5,1991, at river mile 277.49 8 Left 4.94 22.50 7.74 1.65 Middle1 8.12 21.03 6.37 2.26 Right 6.47 6.51 14.46 19.33 6.04 1.94 1.95 9 Left 2.13 18.15 20.48 .69 Middle 2.13 15.94 19.04 .69 Right1 2.18 2.15 16.82 16.97 19.42 .70 .69 10 Right 1.52 15.05 30.78 .51 11 Middle 1.06 14.89 43.53 .36 Subreach 4A - Injected 10.31 liters of rhodamine WT, 20-percent dye at 0700 on August 5,1991, at river mile 254.73 11 Left 3.29 13.04 11.15 .95 Middle1 3.42 13.49 10.94 1.03 Right 2.99 323 15.31 13.95 12.24 .86 .95 12 Left 1.16 12.29 29.17 .37 Middle1 1.16 11.81 27.04 .40 Right 1.10 1.14 11.03 11.71 28.07 .36 .38 13 Middle .82 11.43 45.01 .29 Subreach 4B - Injected 10.31 liters of rhodamine WT, 20-percent dye at 0500 on August 5,1991, at river mile 231.97 13 Left 3.61 13.24 8.29 1.00 Middle1 4.69 15.62 7.30 1.30 Right 4.05 4.12 13.06 13.97 7.48 1.10 1.13 14 Left 1.00 13.00 29.45 .32 Middle1 1.13 13.32 26.46 .38 Right 1.17 1.10 13.52 13.28 26.13 .38 .36 15 Middle .71 12.16 40.13 .24 1 Site selected for traveltime analyses. 13 Table 5. Time-concentration curve peak concentrations, areas, and centroids for the August surge-wave studies on the Delaware River [jig/L, microgram per liter; hr, hour] Time-concentration-curve centroid Area under Average Time- Peak Average peak Site Transect time-concen time-concen Average concentration concentration Time since averaged concen number location tration curve tration area injection concen (W/L) (WI/L) tration G*g/L)*hr (hr) tration (MO/L) (H9 Cannonsville Reservoir release -Injected 5.00 liters of rhodamine WT, 20-percent dye at 0500 on August 14,1991, at river mile 330.50 1 Left1 5.54 15.69 10.00 1.86 Middle 5.38 15.27 9.81 1.89 Right 5.49 5.47 15.46 15.47 10.02 1.93 1.89 2 Left 1.30 8.85 26.89 .43 Middle1 1.47 8.41 25.86 .48 Right 1.30 1.36 9.16 8.81 27.08 .44 .45 Lake Wallenpaupack release - Injected 5.00 liters of rhodamine WT, 20-percent dye at 0630 on August 8,1991, at river mile 275.50 8 Left 2.87 5.60 3.77 .93 Middle1 11.80 6.92 2.62 3.53 Right 5.54 6.74 7.73 6.75 3.66 1.29 1.92 9 Left 1.13 5.72 16.25 .29 Middle1 1.39 4.98 14.45 .35 Right 1.13 1.22 5.21 5.30 15.78 .29 .31 Rio Reservoir release - Injected 5.00 liters of rhodamine WT, 20-percent dye at 1030 on August 7,1991, at river mile 257.05 10 Left 2.30 6.32 4.87 .70 Middle1 8.48 4.53 2.57 2.36 Right 7.16 5.98 5.01 5.29 2.65 1.94 1.67 11 Left1 .79 4.46 13.27 .26 Middle .74 4.75 13.31 .26 Right .65 .73 4.64 4.62 14.40 .22 .25 1 Site selected for traveitime analyses. 14 2.8 ijjce *'b, R Ij o: 2.4 ESHBACK INJECTION (SEPARATED) LJ Q_ PORT JERVIS INJECTION (SEPARATED) 00 2-2 OBSERVED DYE CLOUDS 1 2 O go 1-8 LJ z 1 - U.on Q LJ O 0.6 - 0.4 - 0.2 - 26 28 30 32 34 36 38 40 TIME SINCE INJECTION, IN HOURS Figure 5. Separation of time-concentration curve for the Eshback Access and Port Jervis dye injection, May 6, 1991. 15 RIVER DISCHARGE Knowledge of streamflow is essential when attempting to predict how a spill will move. Five continuous-record streamflow-measurement stations are operated within the study reach. These stations were used to monitor discharge during the study and are to be used as index stations when estimating the traveltime of a contaminant spill. Because the subreaches overlap, each subreach includes at least one index station where stage is recorded (and discharge can be calculated) at 15-minute intervals. The streamflow-measurement stations are operated by the USGS offices located in Albany, N.Y., and West Trenton, N.J., and are listed in table 1. Discharges for each streamflow-gaging station for the medium-flow and low-flow studies are given in figures 6-10. Discharge generally was decreasing during the studies except during the medium-flow study when a rainstorm caused an increase in discharge in the lower part of the study reach. Most of the hydrographs of discharges during the low-flow studies show a sharp increase on August 7 or 15. This "jump" marks the arrival of the water from the reservoir releases at each streamflow-measurement station. The hydrograph for the streamflow-gaging station Delaware River near Delaware Water Gap shows a constant discharge during most of the August 5-7 study. This occurred because of instrument malfunction at the station. Comparison of this hydrograph with that for the station at Montague, N.J., and consideration of the inflow between the two stations were used to confirm that the determined discharges during passage of the dye cloud are acceptable estimates. Traveltime and discharge are inversely related. Traveltime must be related to a site-specific discharge in order to reliably estimate traveltimes at different river locations over a range of discharges. Tributary inflow may have a substantial effect on discharge. Because of the potential for large changes in discharge at different river locations, a method of relating flows throughout the study reach is necessary. Flow duration is a useful index for comparing streamflows at any point along a river. Searcy (1959) defines flow duration as "a cumulative frequency that shows the percentage of time that specified discharges are equalled or exceeded." Flow durations were computed for 1976-91. During the May 1991 medium-flow study, the average discharge was at about the 25-30-percent flow duration for all stations. The flow duration for the August low-flow study was at the 85-95-percent flow duration. Figure 11 shows the relation between flow duration and discharge for the five streamflow stations in the study reach. Each of the index stations is equipped with phone access capability, which permits access to real- time discharge data for those responsible for responding to a contaminant spill. 16 DISCHARGE, IN CUBIC FEET PER SECOND DISCHARGE, IN CUBIC FEET PER SECOND ro to ^ tn o> -j OD too - ro co .u Ol O> -x| 03 I\J g ^ (O 8 ;'EndofsubreaclT2A 8 p -< sampling z (O End of subreach 1 , r< 0> sampling 8 End of subreach 1 i\j (O - (O sampling - ^>5s? i i i 1 I'll 8 10,000 9,000 O Z 8,000 MAYS MAY 9 O 7,000 HI CO 6 000 tr it! 5,000 HI W 4,000 01428500 Delaware River above Lackawaxen River o near Barryville, N.Y. CO ID 3,000 O HI C? 2,000 m I 1 O CO °~ o "o« 1,000 2400 0400 0800 1200 1600 2000 2400 0400 0800 1200 1600 2000 2400 HOURS 1( I I \ \ 8,000 7,000 o 6,000 5,000 AUGUST 12 AUGUST 13 AUGUST 14 AUGUST 15 o o 4,000 LU CO 3,000 cc HI Q_ 2,000 HI HI U. O CO 800 ID 700 O 600 500 HI 400 O ;£*;£'8 8 CC 300 < m < I CM C\l o 200 CO o t o 11 (A (O 100 2400 0800 1600 2400 0800 1600 2400 0800 1600 2400 0800 1600 2400 HOURS Figure 7. Discharge of Delaware River above Lackawaxen River near Barryville, N.Y, May 8-9 and August 12-15, 1991. 18 IU.UUU i i i | i | i ill 9,000 - Q 8,000 O MAY 6 MAY 7 o 7,000 LU " ~~ N. CO 6,000 ^ ^ f cc ^^^"^ >w ^__^X LU ^-*~"*"^'*^ \- '^ "^ 0- 5,000 ___ ^^"^^ 1- *^~ LU LU 4,000 LU I 01 434000 Delaware River at Port Jervis, N.Y O / QD ^_y 3,000 - O z LU O 2,000 o c ^, cc 11 ^ M c" ®, "5 "o I " C CO CO o CO ^ 5 |gg? Q 1CD 1CD u_3 fp-»*2 tr- 22 ° S ° S "3 "3 ? ? CO CO LU UJ 1 nnn 111 1 1 1 1 II 1 1 1 2400 0400 0800 1200 1600 2000 2400 0400 0800 1200 1600 2000 2400 HOURS IU,WU I I I I l l | I 1 I 9,000 8,000 - - AUGUSTS AUGUST 6 AUGUST 7 o 7,000 o - LU 6,000 CO cc 5,000 - - LU Q_ h- 4,000 - LU LU U_ O 3,000 - QD Z> CD O 75. c LU 2,000 .Q c O Cg 0 1434000 Delaware River at Port Jervis, N.Y. / |fi cc '£? «S / ^a < ^ 5 -|" _ ____ / ggV -* 5 -5 o 'o'o100) T3T3 CC CO CO liUli 1 OOO I I I i i i i i Mi 2400 0600 1200 1800 2400 0600 1200 1800 2400 0600 1200 1800 2400 HOURS Figure 8. Discharge of Delaware River at Port Jervis, N.Y., May 6-7 and August 5-7,1991. 19 DISCHARGE, IN CUBIC FEET PER SECOND DISCHARGE, IN CUBIC FEET PER SECOND CO ttl O5 "vl CD (D O CD 8 8 8 8 8 8 8 8 gco' 8 o 0) § o ro O 8 =1 8 5f 8 o CO c 8 C (D O ri O O £ c o t/> 3D o 5 t End of subreach 4A sampling C7> * End of subreach 3 sampling 0) Q. > sr CO CO CD C ro O 8 End of subreacl CD CO End of subreach ro 8 8 10,000 9,000 - Q 2 8,000 - O 7,000 - LU CO 6.000 DC LU Q. 5.000 01440200 Delaware River near Delaware Water Gap, Pa. 4.000 o co =) 3,000 o MAY 6 MAY 7 LU CE 2,000 I O co Q 1,000 2400 0400 0800 1200 1600 2000 2400 0400 0800 1200 1600 2000 2400 HOURS 1 U,WU I I I ] I I I I I I I 9,000 - - 8,000 . . Q AUGUSTS AUGUST 6 AUGUST 7 2 7,000 O - LJJ 6,000 _ CO DC 5.000 . . LU Q. IT] 4.000 . ... ESTIMATED LU U_ ^ 3.000 . . CO ID O 2 01440200 Delaware River near Delaware Water Gap, Pa o LU 2.000 CDTj' O OJ DC ...... £" --' - B m ? O> X 5 Aw'o. C O t p CO £ -0 B) Q 3 CO 111 1 OOO II I I i i i 1 1 1 2400 0600 1200 1800 2400 0600 1200 1800 2400 0600 1200 1800 2400 HOURS Figure 10. Discharge of Delaware River below Tocks Island Damsite, near Delaware Water Gap, Pa. May 6-7 and August 6-7,1991. 21 20,000 10,000 Q 9,000 5 8,000 O 7.000 °> 6,000 CC £ 5.000 uS 4,000 LL § 3,000 O -_ 2,000 UJ Delaware Water Gap, Pa. Montague, N.J. Port Jervis, N.Y. 1,000 900 800 Barryville, N.Y. 700 Callicoon, N.Y. 600 500 10 20 30 40 50 60 70 80 90 95 98 99 FLOW DURATION, IN PERCENT Figure 11. Relation between discharge and flow duration at index streamf low-measurement stations on the Delaware River. 22 TRAVELTIME Measured Curves of the dye concentrations as a function of time since dye injection were used to determine the traveltimes of the leading edge, peak concentration, and trailing edge of the dye cloud. The medium-flow and low-flow time-concentrations curves for each sampling site are shown in figures 12 and 13, respectively. The trailing edge is the point at which the dye concentration has decreased to 10 percent of the peak concentration at each sampling site. Figure 14 shows the accumulated traveltimes of each of the three dye cloud components for both the May and August dye studies. Tables 6 and 7 summarize the traveltimes for the two studies. Irregularities in the time-concentration curves are attributed to the incomplete mixing of the dye. Some factors that affect mixing are eddy zones, curves, pools, riffles, bridge piers and flow regulation. The curves representing the Bushkill to Kittatinny subreach (subreach 4B) illustrate the overlap of the dye clouds resulting from the Port Jervis and Eshback injections. Dye-cloud velocities and stream discharge, determined under medium- and low-flow conditions, were used to estimate dye-cloud velocities for flow durations ranging from 30 to 95 percent. The relation between velocity and discharge is typically linear when plotted on logarithmic paper (Hubbard and others, 1982, p. 30). The velocities of the leading edge, peak concentration, and trailing edge of the dye cloud between successive sampling sites were calculated for both dye studies by dividing the segment length by the traveltimes. The representative discharge for each stream segment was calculated using the time-weighted average discharge measured at the nearest index station(s). The representative discharges were determined for the traveltime of the dye cloud between adjacent sites for each of the three dye-cloud components. Table 8 shows the velocities and representative discharges for each dye-cloud component during the August and May studies for the river reach between Cochecton, N.Y., and Narrowsburg, N.Y. For example, figure 15 shows the dye-cloud velocities as a function of the average discharges at the streamflow-measurement stations at Callicoon and above Lackawaxen near Barryville. Dye-cloud velocities at discharges corresponding to flow duration of 30,40, 50, 60, 70, 75, 80, 85, 90, and 95 percent were determined assuming a linear relation and are shown in table 9 for the river reach between Cochecton, N.Y., and Narrowsburg, N.Y. In this manner, incremental velocities for each dye-cloud component were determined over the range of flow durations for all 15 stream segments. Where two index stations are included in a particular subreach, plots were made for both, and the results were averaged. Adjusting the estimated discharge at Delaware River near Delaware Water Gap during the August 5-7 study by 5 percent resulted in changes in velocity of less than 3 percent over the range of flow durations. The estimated discharge for August 5-7 as shown in figure 10 was used in the velocity computations with little loss of accuracy. Each segment length was divided by each of the 10 incremental velocities to determine the traveltime of the leading edge, peak concentration, and the trailing edge over the range of discharges. The resulting traveltimes were cumulated from Hancock, N.Y, to the Delaware Water Gap. The traveltimes for the entire study reach for the leading edge, peak concentration, and trailing edge are given in tables 10,11, and 12, respectively, and in figures 16,17, and 18, respectively. Use of these tables and figures provides the reader with a method of estimating the time for a soluble substance to travel between two points in the study reach over a range of flows. The sampling point at Dingmans during the May study was 0.5 mi upstream from the August sampling location. The different segment lengths result in different cumulative traveltimes from the Dingmans site down to Kittatinny. Because the variation in traveltimes was within 1 percent, the average of the two traveltimes was used. Duration is the time it takes for the entire dye cloud to move past a point in the river. Duration can be determined by subtracting the leading-edge traveltime from the trailing-edge traveltime. This calculation was done for the 10 flow durations for each stream segment. The results of these calculations are given in table 13 and are graphically presented in figure 19. 23 SUBREACH 1 DYE INJECTED AT HANCOCK, N.Y. (RIVER MILE 330.5) NUMBER IS SAMPLING SITE o I 5 O O 2 10 15 20 25 30 TIME SINCE INJECTION. IN HOURS 40 n 3 35 SUBREACH 2A £30 DYE INJECTED AT CALLICOON, N.Y. (RIVER MILE 303.6) ^20 u. 015 10 85 0 2 4 6 8 10 12 14 16 18 20 22 24 26 TIME SINCE INJECTION, IN HOURS Figure 12A. Observed time-concentration curves from the May 1991 medium-flow study for subreach 1 and subreach 2A. 24 SUBREACH 2B DYE INJECTED AT NARROWSBURG, N.Y. (RIVER MILE 289.4) K 4 NUMBER IS SAMPLING SITE O O z o I I 6 8 10 12 14 16 TIME SINCE INJECTION, IN HOURS SUBREACH 3 DYE INJECTED NEAR CONFLUENCE OF 1326 LACKAWAXEN RIVER (RIVER MILE 277.5) 01 £24 NUMBER IS SAMPLING SITE I(/) 22 g20 o: 16 £ S14 u. O 12 5 U 6 10 84 11 2 0 8 10 12 14 16 18 20 22 24 26 TIME SINCE INJECTION, IN HOURS Figure 12B. Observed time-concentration curves from the May 1991 medium-flow study for subreach 2B and subreach 3. 25 20 18 SUBREACH 4A DYE INJECTED AT PORT JERVIS, N.Y (RIVER MILE 254.7) 16 NUMBER IS SAMPLING SITE i(A 14 o o £12 Estimated curve L. o O 8 Z O 5 6 13 8, 8 10 IS 20 25 30 35 TIME SINCE INJECTION, IN HOURS 10 SUBREACH 4B DYE INJECTED AT ESHBACK ACCESS (RIVER MILE 232.0) NUMBER IS SAMPLING SITE ICO 7 o o Estimated curve CK 6 O - 5 Cl Z O O 2 O O 10 is 20 25 TIME SINCE INJECTION, IN HOURS Figure 12C. Observed time-concentration curves from the May 1991 medium-flow study for subreach 4A and subreach 4B. 26 10 SUBREACH 1 DYE INJECTED AT HANCOCK. N.Y. (RIVER MILE 330.5) NUMBER IS SAMPLING SITE (ft o o g 6 o § 3 o o 10 20 30 40 SO so 7O 80 TIME SINCE INJECTION, IN HOURS 20 18 cc fc SUBREACH 2A _l'16 DYE INJECTED AT CALLICOON, N.Y. (RIVER MILE 303.6) B NUMBER IS SAMPLING SITE Q. (ft 14 O 0: o fe 8 O O o 10 20 30 40 50 60 70 TIME SINCE INJECTION, IN HOURS Figure 13A. Observed time-concentration curves from the August 1991 low-flow study for subreach 1 and subreach 2A. 27 SUBREACH 2B DYE INJECTED AT NARROWSBURG, N.Y. (RIVER MILE 289.4) tfcc NUMBER IS SAMPLING SITE 4 O go 2 o §2 I 1 10 15 20 25 30 35 40 45 TIME SINCE INJECTION, IN HOURS 10 SUBREACH 3 DYE INJECTED NEAR MOUTH OF LACKAWAXEN RIVER (RIVER MILE 277.5) to NUMBER IS SAMPLING SITE icc o o § s Ife 4 z o J= 3 O 2 10 O O 11 1 10 15 20 25 30 35 40 45 50 55 60 TIME SINCE INJECTION, IN HOURS Figure 13B. Observed time-concentration curves from the August 1991 low-flow study for subreach 2B and subreach 3. 28 SUBREACH 4A DYE INJECTED AT PORT JERVIS, N.Y (RIVER MILE 254.7) NUMBER IS SAMPLING SITE Estimated curve O z O O 1 O O 10 15 20 25 30 35 40 50 55 60 TIME SINCE INJECTION, IN HOURS 13 QL 5 SUBREACH 4B DYE INJECTED AT ESHBACK ACCESS (RIVER MILE 232.0) NUMBER IS SAMPLING SITE a: O O * Z O en Si O O 10 15 20 25 30 35 40 45 50 55 60 TIME SINCE INJECTION, IN HOURS Figure 13C. Observed time-concentration curves from the August 1991 low-flow study for subreach 4A and subreach 4B. 29 160 150 SAMPLING SITE NUMBER 140 45 6 7 8 9 13 14 15 II I I I I 130 120 MAY 1991 110 100 LEADING EDGE O PEAK CONCENTRATION I 90 TRAILING EDGE s-Ut 80 2 60 50 40 30 20 10 340 320 300 280 260 240 220 200 RIVER MILES UPSTREAM FROM MOUTH 360 340 SAMPLING SITE NUMBER 320 13 14 15 300 I I 280 260 2*0 AUGUST 1991 ^o LEADING EDGE 200 PEAK CONCENTRATION TRAILING EDGE u 180 160 LJ 140 120 100 80 60 40 20 340 320 300 280 260 240 220 200 RIVER MILES UPSTREAM FROM MOUTH Figure 14. Cumulated traveltime for May and August 1991 medium- and low-flow dye injections, Delaware River, Hancock, N.Y., to the Delaware Water Gap. 30 Table 6. Traveftimes for the May medium-flow dye study, Delaware River, Hancock, N. Y., to the Delaware Water Gap [All times are in hours.] Leading edge Peak concentration Trailing edge Travel- Cumul Travel- Cumul Travel- Cumul Site Time Time Time time ative number since time ative ative since time between travel- since between travel- between travel- injection injection injection sites time sites time sites time Subreach 1 1 3.00 3.00 3.00 3.33 3.33 3.33 4.43 4.43 4.43 2 11.00 8.00 11.00 12.33 9.00 12.33 16.32 11.89 16.32' 3 19.00 8.00 19.00 21.25 8.92 21.25 27.62 11.30 27.62 Subreach 2A 3 2.85 2.85 21.85 3.02 3.02 24.27 4.03 4.03 31.65 4 6.58 3.73 25.58 7.50 4.48 28.75 10.35 6.32 37.97 5 7.58 1.00 26.58 8.72 1.22 29.97 16.43 6.08 44.05 6 10.25 2.67 29.25 12.25 353 33.50 20.44 4.01 48.06 Subreach 2B 6 2.43 2.43 31.68 2.93 2.93 36.43 4.24 4.24 52.30 7 6.00 3.57 35.25 6.67 3.74 40.17 9.09 4.85 57.15 8 8.25 225 37.50 9.75 3.08 4325 12.68 3.59 60.74 Subreach 3 8 2.23 2.23 39.73 2.57 2.57 45.82 3.43 3.43 64.17 9 6.99 4.76 44.49 8.00 5.43 51.25 11.34 7.91 72.08 10 11.82 4.83 49.32 13.82 5.82 57.07 18.14 6.80 78.88 11 16.17 4.35 53.67 18.83 5.01 62.08 24.87 6.73 85.61 Subreach 4A 11 3.93 3.93 57.60 4.92 4.92 67.00 6.70 6.70 92.31 12A 9.57 5.64 63.24 10.83 5.91 72.91 15.48 . 8.78 101.09 13 15.84 6.27 69.51 18.28 7.45 80.36 25.01 9.53 110.62 14 21.92 6.08 75.59 25.53 725 87.61 35.13 10.12 120.74 15 26.42 4.50 80.09 30.63 5.10 92.71 41.81 6.68 127.42 Subreach 4B 13 114.57 1.99 65.23 hs.oo 2.42 75.33 !16.75 4.17 10526 14 !20.33 5.76 70.99 ^.OS 7.08 82.41 !26.77 10.02 11528 15 !24.83 4.50 75.49 !27.33 525 87.66 !34.69 7.92 12320 1 Times adjusted to reflect injection at river mile 254.73 (subreach 4A). 31 Table 7. Traveltimes for the August Sow-flow dye study, Delaware River, Hancock, N. Y., to the Delaware Water Gap [All times are in hours.] Leading edge Peak concentration Trailing edge Travel- Cumul Travel- Cumul Travel- Cumul Site Time Time Time time ative time ative ative number since since time between travel- between travel- since travel- injection injection between sites time sites time injection sites time Subreach 1 1 7.00 7.00 7.00 7.75 7.75 7.75 12.33 12.33 12.33 2 26.50 19.50 26.50 32.67 24.92 32.67 47.67 35.34 47.67 3 49.33 22.83 49.33 60.33 27.66 60.33 74.16 26.49 74.16 Subreach 2A 3 6.75 6.75 56.08 8.83 8.83 69.16 14.50 14.50 88.66 4 1625 9.50 65.58 20.83 1100 81.16 31.02 16.52 105.18 5 19.08 2.83 68.41 27.08 6.25 87.41 53.50 22.48 127.66 6 26.00 6.92 75.33 36.00 8.92 96.33 66.18 12.68 140.34 Subreach 2B 6 5.83 5.83 81.16 7.08 7.08 103.41 13.86 13.86 15420 7 15.43 9.60 90.76 19.18 12.10 115.51 30.68 16.82 171.02 8 2025 4.82 95.58 29.00 9.82 125.33 38.28 7.60 178.62 Subreach 3 8 3.70 3.70 99.28 4.65 4.65 129.98 9.70 9.70 188.32 9 12.08 8.38 107.66 16.42 11.77 141.75 27.83 18.13 206.45 10 21.83 9.75 117 Al 27.83 11.41 153.16 41.04 13.21 219.66 11 30.33 8.50 125.91 38.35 10.52 163.68 56.17 15.13 234.79 Subreach 4A 11 7.00 7.00 132.91 9.17 9.17 172.85 16.15 16.15 250.94 12B 19.10 12.10 145.01 24.77 15.60 188.45 39.64 23.49 274.43 13 32.80 13.70 158.71 39.42 14.65 203.10 60.50 20.86 295.29 Subreach 4B 13 4.00 4.00 162.71 4.93 4.93 208.03 11.22 11.22 306.51 14 15.18 11.18 173.89 22.00 17.07 225.10 39.20 27.98 334.49 15 24.50 9.32 183.21 34.00 12.00 237.10 57.59 18.39 352.88 Table 8. Dye-cloud velocities and representative stream discharges for leading edge, peak, and trailing edge of dye cloud for reach of the Delaware River between Cochecton, N. Y., and Narrowsburg, N. Y. [ft3/s, cubic foot per second] Velocity Discharge at Discharge above Date (miles per hour) Callicoon (ft^s) Lackawaxen (tf/s) Peak Aug. 12 0.67 571 713 May 8 1.80 3,023 3,602 Leading edge Aug. 12-13 .82 580 732 May 8 2.14 3,037 3,621 Trailing edge Aug. 12-13 .46 550 687 May 8 128 2,980 3,541 32 - LEADING EDGE PEAK CONCENTRATION TRAILING EDGE 1 0.9 0.8 0.7 0.6 CALLICOON 0.5 0.4 500 1,000 2,000 3,000 4.000 5,000 DISCHARGE AT CALLICOON __ - LEADING EDGE . PEAK CONCENTRATION . TRAILING EDGE Z 1 £ 0.9 g 0.8 UJ > 0.7 0.6 ABOVE LACKAWAXEN NEAR 0.5 BARRYVILLE 0.4 500 1,000 2,000 3,000 4,000 5,000 DISCHARGE AT ABOVE LACKAWAXEN NEAR BARRYVILLE Figure 15. Dye-cloud velocity as a function of average discharges at streamflow-measurement stations Delaware River at Callicoon, N.Y., and above Lackawaxen near Barryville, N.Y 33 Table 9. Dye-cloud velocities at discharges corresponding to various flow durations at Delaware River at Callicoon, N. Y., and Delaware River above Lackawaxen River near Barryville, N. Y. [ft3/s, cubic foot per second; Cal, Callicoon; Lack, Lackawaxen; Avg., average] Flow duration Velocity (miles per hour) Discharge (ftVs) Peak Leading edge Trailing edge Percent Cal Lack Cal Lack Avg. Cal Lack Avg. Cal Lack Avg. 30 2,400 2,690 1.56 1.50 1.53 1.87 1.75 1.81 1.13 1.08 1.10 40 1,730 1,970 1.29 1.25 1.27 1.56 1.47 1.52 .925 .890 .908 50 1,420 1,580 1.15 1.09 1.12 1.38 1.30 1.34 .815 .770 .792 60 1,240 1,380 1.06 1.00 1.03 1.28 1.20 1.24 .755 .710 .732 70 1,100 1,240 .990 .940 .965 1.20 1.13 1.16 .700 .665 .682 75 1,030 1,160 .950 .900 .925 1.16 1.08 1.12 .670 .640 .655 80 947 1,070 .900 .860 .880 1.11 1.04 1.08 .640 .610 .625 85 868 980 .860 .820 .840 1.05 .990 1.02 .605 .575 .590 90 789 890 .810 .770 .790 .990 .940 .965 .572 .540 .556 95 674 760 .740 .700 .720 .910 .860 .885 .510 .490 .500 34 Table 10. Traveltimes for leading edge of dye cloud at selected flow durations on the Delaware River, Hancock, N. Y. to the Delaware Water Gap Distance Traveltime (hours) of leading edge of dye cloud between from river mile 330.50 for the indicated flow duration (percent) River Site Site name sampling number mile1 sites 30 40 50 60 70 75 80 85 90 95 (miles) Inject Hancock wastewater treatment plant 330.50 0.00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1 Buckingham Access 325.14 5.36 3.4 4.1 4.5 4.8 5.2 5.4 5.6 5.8 6.2 6.7 2 Kellam's Bridge 312.59 12.55 12.3 14.8 16.2 17.6 18.8 19.6 20.3 21.3 22.5 24.4 3 Cochecton Bridge 298.40 14.19 21.1 25.7 28.7 31.2 33.4 34.9 36.5 38.4 40.6 44.6 4 Narrowsburg (N.Y. access) 290.34 8.06 25.5 31.0 34.7 37.6 40.4 42.1 43.9 46.3 49.0 53.8 5 Narrowsburg (Pa. access) 289.43 .91 26.7 32.4 36.3 39.4 42.3 44.1 46.0 48.5 51.4 56.4 6 Tenmile River confluence 284.15 5.28 29.8 36.3 40.6 44.0 47.1 49.2 51.2 54.0 57.1 62.6 7 Lacka waxen River confluence 277.81 6.34 33.9 41.3 46.4 50.4 53.8 56.4 58.9 62.0 65.7 72.2 8 Barryville Bridge 273.50 4.31 36.7 44.5 49.9 54.1 57.6 60.3 63.0 66.2 70.1 76.9 9 Pond Eddy Bridge 265.50 8.00 41.1 49.8 55.8 60.8 65.0 68.0 70.8 74.4 78.6 85.8 10 Port Jervis Bridge 254.75 10.75 46.1 55.7 62.8 68.7 73.9 77.3 80.4 84.2 88.9 96.6 11 Milford Beach 246.31 8.44 50.6 61.0 69.0 75.6 81.7 85.3 88.7 92.7 97.8 106 n 12 Dingmansz 238.98 7.33 56.0 67.6 76.8 84.6 82.0 96.0 99.8 104 110 119 13 Bushkill Access 228.11 10.87 62.2 75.0 85.9 95.3 104 109 113 118 124 134 14 Smithfield Beach 218.34 9.77 68.2 82.0 93.8 104 114 119 123 128 135 146 15 Kittatinny Access 211.37 6.97 73.0 87.4 100 111 122 127 132 138 145 155 1 River mile zero is located at the mouth of the Delaware Bay. 2 The relocation of the Dingmans site is reflected in reach-segment average velocities from Dingmans through Kittatinny Access which, in turn, present a slight variation in trave times. Analyses in this report use the average of these traveltimes. Table 11. Traveltimes for peak concentration of dye cloud at selected flow durations on the Delaware River, Hancock, N. Y., to the Delaware Water Gap Distance Traveltime (hours) for peak concentration of dye cloud between from river mile 330.50 for the indicated flow duration (percent) Site Site name River sampling number mile1 sites 30 40 50 60 70 75 80 85 90 95 (miles) Inject Hancock wastewater treatment plant 330.50 0.00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1 Buckingham Access 325.14 5.36 3.8 4.6 5.1 5.5 5.8 6.1 6.3 6.6 7.0 7.7 2 Kellam's Bridge 312.59 12.55 14.1 17.1 19.2 20.8 22.1 23.1 24.2 25.4 27.0 29.6 3 Cochecton Bridge 298.40 14.19 23.8 29.3 33.1 35.9 38.6 40.4 42.4 44.8 47.5 52.6 4 Narrowsburg (N.Y. access) 290.34 8.06 29.1 35.6 40.3 43.7 47.0 49.1 51.6 54.4 57.7 63.8 5 Narrowsburg (Pa. access) 289.43 .91 30.6 37.7 43.0 46.6 50.3 52.7 55.5 58.7 62.5 69.3 6 Tenmile River confluence 284.15 5.28 34.6 42.5 48.3 52.4 56.5 59.1 62.1 65.6 69.8 77.3 7 Lacka waxen River confluence 277.81 6.34 39.4 48.4 55.3 60.2 64.6 67.8 71.4 75.6 80.5 89.3 8 Barryville Bridge 273.50 4.31 43.2 53.1 60.8 66.2 71.1 74.6 78.6 83.12 88.6 98.5 9 Pond Eddy Bridge 265.50 8.00 48.3 59.4 68.5 75.2 81.4 85.5 89.7 94.7 101 112 10 Port Jervis Bridge 254.75 10.75 54.4 66.6 76.9 84.6 91.8 96.3 101 106 113 124 11 Milford Beach 246.31 8.44 59.6 72.8 84.3 93.0 101 106 111 117 124 135 12 Dingmans2 238.98 7.33 65.6 80.4 93.6 104 114 120 125 132 140 152 13 Bushkill Access 228.11 10.87 73.0 89.0 104 116 128 134 140 147 155 170 14 Smithfield Beach 218.34 9.77 80.2 98.0 114 128 142 148 155 163 172 188 15 Kittatinny Access 211.37 6.97 86.4 105 123 137 152 159 166 174 184 200 1 River mile zero is located at the mouth of the Delaware Bay. 2 The relocation of the Dingmans site is reflected in reach-segment average velocities from Dingmans through Kittatinny Access which, in turn, present a slight variation in traveltimes. Analyses in this report use the average of these traveltimes. Table 12. Traveltimes for trailing edge of dye cloud at selected flow durations on the Delaware River, Hancock, N. Y., to the Delaware Water Gap Distance Traveltime (hours) for trailing edge of dye cloud between River from river mile 330.50 for the indicated flow duration (percent) Site Site name sampling number mile1 sites 30 40 50 60 70 75 80 85 90 95 (miles) Inject Hancock wastewater treatment plant 330.50 0.00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1 Buckingham Access 325.14 5.36 5.2 6.3 7.0 7.7 8.2 8.6 9.1 9.6 10.1 11.4 2 Kellam's Bridge 312.59 12.55 18.5 22.8 25.8 27.9 30.3 31.9 33.2 35.2 37.4 41.3 3 Cochecton Bridge 298.40 14.19 30.5 37.4 42.3 45.5 48.9 51.9 53.9 57.0 60.6 66.6 4 Narrowsburg (N.Y. access) 290.34 8.06 37.8 46.2 52.5 56.6 60.8 64.2 66.8 70.7 75.2 82.7 5 Narrowsburg (Pa. access) 289.43 .91 45.0 55.3 63.2 68.6 73.8 78.0 81.3 86.1 92.0 102 6 Tenmile River confluence 284.15 5.28 49.5 60.9 69.7 75.6 81.3 85.9 89.6 94.9 101 112 7 Lacka waxen River confluence 277.81 6.34 55.3 68.2 78.5 85.2 91.5 97.0 101 108 115 128 8 Barryville Bridge 273.50 4.31 59.3 72.8 83.6 90.6 97.2 103 107 114 122 135 9 Pond Eddy Bridge 265.50 8.00 67.3 82.5 95.5 105 113 120 125 132 141 155 10 Port Jervis Bridge 254.75 10.75 74.2 90.6 105 115 125 132 138 145 154 169 11 Milford Beach 246.31 8.44 81.6 99.4 115 127 138 146 152 160 170 185 12 Dingmans2 238.98 7.33 90.6 111 130 144 158 167 174 182 193 211 13 Bushkill Access 228.11 10.87 101 123 145 161 177 187 194 204 216 235 14 Smithfield Beach 218.34 9.77 111 136 160 179 199 210 219 230 243 265 15 Kittatinny Access 211.37 6.97 121 146 172 193 214 226 236 248 262 284 1 River mile zero is located at the mouth of the Delaware Bay. 2 The relocation of the Dingmans site is reflected in reach-segment average velocities from Dingmans through Kittatinny Access which, in turn, present a slight variation in trave times. Analyses in this report use the average of these traveltimes. 80 SAMPLING SITE NUMBER to 70 2 I 0 60 1 O O 40 O LJ O 2 < 30 y u. O LU 20 R 10 340 335 330 325 320 315 310 305 300 295 290 285 280 275 RIVER MILES UPSTREAM FROM MOUTH Figure 16A. Relation of traveltime and distance of leading edge of dye cloud at selected flow durations on the Delaware River for sampling sites 1-6, Hancock, N.Y., to 0.1 mile downstream of Tenmile River confluence. 38 200 SAMPLING SITE NUMBER 1BO 10 11 13 I I I I o 160 o 13 g 140 o 120 O 100 O UJ O Z 80 O 30 60 O UJ 5 40 h UJ I 20 h 290 285 280 275 270 265 260 255 250 245 240 235 230 225 220 215 210 205 200 RIVER MILES UPSTREAM FROM MOUTH Figure 16B. Relation of traveltime and distance of leading edge of dye cloud at selected flow durations on the Delaware River for sampling sites 6-15, 0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap. 39 100 oa SAMPLING SITE NUMBER O 90 X 45 O 80 1 O i.i 70 O 60 2 O ;S so O 8 30 30 20 5 Ul 10 340 335 330 325 320 315 310 305 300 295 290 285 280 275 RIVER MILES UPSTREAM FROM MOUTH Figure 17A. Relation of traveltime and distance of peak concentration of dye cloud at selected flow durations on the Delaware River for sampling sites 1-6, Hancock, N.Y., to 0.1 mile downstream of Tenmile River confluence. 40 260 r5 240 SAMPLING SITE NUMBER O I 10 11 12 13 14 15 Z 220 I O 20° O LJ 180 120 LJ O o o 30 tf 80 60 ;= 4o - | 20 h 290 280 270 260 250 240 230 220 210 200 RIVER MILES UPSTREAM FROM MOUTH Figure 17B. Relation of traveltime and distance of peak concentration of dye cloud at selected flow durations on the Delaware River for sampling sites 6-15, 0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap. 41 TRAVELTIME OF TRAILING EDGE OF DYE CLOUD, IN HOURS (D CD 3^ ® 3J -« 3 ' IE O. § fi)a 3 § o O = O (Q ^ . I W O O O OOOUIOUIO Ul (D => FLOW DURATION, IN PERCENT 560 340 - SAMPLING SITE NUMBER a: 320 - 10 11 12 13 14 13 § 300 - 280 - a LU =3 260 - O DC 3 , LU O 240 - Q_ LJ Q 220 - O 20° LJ O 180 - a oLJ 16° - z Zj 140 - ^ 120 - O 100 - LJ 2 80 - 60 - a: 40 - 20 - 0 290 280 270 260 250 240 230 220 210 200 RIVER MILES UPSTREAM FROM MOUTH Figure 186. Relation of traveltime and distance of trailing edge of dye cloud at selected flow durations on the Delaware River for sampling sites 6-15, 0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap. Table 13. Time durations for dye cloud at selected flow durations on the Delaware River, Hancock, N. Y., to the Delaware Water Gap Distance Traveltime (hours) of dye cloud injected at river mile 330.50 between for the indicated flow duration (percent) Site Site name River sampling number mile1 sites 30 40 50 60 70 75 80 85 90 95 (miles) Inject Hancock wastewater treatment plant 330.50 0.00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1 Buckingham Access 325.14 5.36 1.7 2.2 2.6 2.8 3.1 3.3 3.5 3.7 4.0 4.7 2 Kellam's Bridge 312.59 12.55 6.2 8.0 9.6 10.3 11.5 12.3 12.9 13.9 14.9 16.9 3 Cochecton Bridge 298.40 14.19 9.4 11.6 13.6 14.3 15.5 17.0 17.5 18.6 20.0 22.0 4 Narrowsburg (N.Y. access) 290.34 8.06 12.3 15.2 17.8 19.0 20.4 22.1 22.9 24.4 26.2 29.0 5 Narrowsburg (Pa. access) 289.43 .91 18.3 22.9 26.9 29.2 31.5 33.9 35.3 37.6 40.6 45.3 6 Tenmile River confluence 284.15 5.28 19.7 24.6 29.2 31.6 34.2 36.8 38.3 40.9 44.3 49.5 7 Lackawaxen River confluence 277.81 6.34 21.4 26.9 32.0 34.8 37.7 40.6 42.5 45.6 49.4 55.4 8 Barryville Bridge 273.50 4.31 22.5 28.3 33.6 36.6 39.5 42.4 44.5 47.6 51.5 57.7 9 Pond Eddy Bridge 265.50 8.00 26.2 32.8 39.6 43.8 48.2 51.6 54.2 57.6 62.2 69.2 10 Port Jervis Bridge 254.75 10.75 28.1 34.9 42.1 46.4 51.1 54.6 57.3 60.8 65.3 72.6 11 Milford Beach 246.31 8.44 31.0 38.4 46.2 51.4 56.7 60.4 63.3 67.0 71.9 79.5 12 Dingmans2 238.98 7.33 39.6 43.2 53.3 59.2 66.2 70.6 74.0 78.2 83.6 92.8 13 Bushkill Access 228.11 10.87 38.4 47.8 58.8 65.3 73.0 77.8 81.4 85.9 91.8 101 14 Smithfield Beach 218.34 9.77 42.8 53.6 66.6 75.4 85.4 91.2 95.9 101 108 119 15 Kittatinny Access 211.37 6.97 48.0 58.3 72.2 81.8 82.8 98.8 104 110 117 128 1 River mile zero is located at the mouth of the Delaware Bay. 2 The relocation of the Dingmans site is reflected in reach-segment average velocities from Dingmans through Kittatinny Access which, in turn, present a slight variation in traveltimes. Analyses in this report use the average of these traveltimes. 70 SAMPLING SITE NUMBER 60 2 45 ex o 50 I LJJ O QC Q LD 3" Q. z. O 30 o Q o 40 I o: 20 30 10 340 335 330 325 320 315 310 305 300 295 29G 285 280 275 RIVER MILES UPSTREAM FROM MOUTH Figure 19A. Relation between dye cloud duration and distance at selected flow durations on the Delaware River for sampling sites 1-6, Hancock, N.Y., to 0.1 mile downstream of Tenmile River confluence. The data presented in figures 16-19 and tables 9-12 indicate that the traveltime for the leading edge of a spill at Buckingham Access (site 1) to reach the Delaware Water Gap would be about 70 hours if flows were at the 30-percent flow duration and 155 hours if flows were at the 95-percent flow duration. Traveltimes for the peak concentration would be about 85 hours and 200 hours for the 30-percent and 95-percent flow durations, respectively. The trailing edge would take about 120 hours at the 30-percent flow duration and about 290 hours at the 95-percent flow duration to travel the same distance. The duration of this hypothetical spill at the Water Gap would be about 45 hours and 130 hours at the 30-percent and 95-percent flow durations, respectively. The duration of the spill is directly related to the time since the spill occurred, location of the spill, flow, and dispersion characteristics. Figures 16 to 19 show a large increase in dye-cloud travel time between sampling sites 4 and 5, a segment of less than 1 mi containing the Narrowsburg pool and eddy. At the pool and eddy, depths range from about 20 ft to over 110 ft and then recover within a distance of less than 3,000 ft. During the Narrowsburg dye injection, three points in the transect entering the pool were sampled, three locations within the eddy were sampled (one of which involved vertical sampling to a depth of 85 ft), and one point downstream of the pool was sampled. This sampling was done to determine the effect of the pool on the dye clouds for the two subsequent dye injections. A vertical temperature profile was taken in the pool to determine the presence of stratification in the water column that might affect the movement of dye. This profile showed a difference of less than 0.5°C between the surface temperature and the temperature at 110 ft. Vertical dye sampling at depths of 1,15, 30,45, and 85 ft showed that with time the dye concentrations 45 180 SAMPLJNG SITE NUMBER 160 10 11 12 13 14 15 140 o 120 LU crO 100 O UJ so o O o O 60 40 30 Q 40 20 290 280 270 260 250 240 230 220 210 200 RIVER MILES UPSTREAM FROM MOUTH Figure 19B. Relation between dye cloud duration and distance at selected flow durations on the Delaware River for sampling sites 6-15, 0.1 mile downstream of Tenmile River confluence to the Delaware Water Gap. increased with depth, while decreasing on the surface. This indicates continued vertical mixing, surface velocity stripping of the upper layers of the dye cloud, and, to some degree, the vortex of the eddy at this location. Tables 14 and 15 show the effect of the pool on traveltime of the dye cloud. The peak concentration exiting the pool was reduced by a ratio of about 4:1. A comparison of dye-cloud durations at the upstream and downstream end of the pool show an increase of over 50 percent in the time required for passage of the dye doud. Figure 20 illustrates the elongation of the trailing edge of the dye cloud after passing through the pool. 46 Table 14. Traveltimes, areas, and centroids of the dye cloud for the Delaware River at Narrowsburg pool study, May 1,1991 Time since injection (hour) Dye-cloud centroid Peak Area under Site Transect River Peak concen time concen Concen number location mile Leading concen Trailing Time since edge edge tration tration curve injection tration tration Injected 10.31 liters of 20 percent Rhodamine WT dye at 0626 hours on May 1, 1991, at river mile 295.33 4 Left 2.43 2.85 4.10 14.40 8.50 3.26 3.54 Middle 2.42 2.83 3.27 16.05 6.38 2.90 4.46 Right 290.34 2.40 3.15 4.13 6.69 5.20 3.28 2.04 5 Middle 289.43 3.57 4.07 8.06 4.15 7.67 6.21 .88 Table 15. Dye-cloud velocities and durations for the Delaware River at Narrowsburg pool study, May 1, 1991 Location Distance Leading edge Peak concentration Trailing edge ^^ "5T 3 3 3 %. "35" O O O O T^Z * "* ^-^ *^f -w 03" 3 £ 3 W __ (0 (O O ^^ ^ ? s "§" E1 £. £ £ '55 O 10 O 'w o (0 TJ C C *= c c -= c c -= o 3 0 O 03 Jr O Q3 Jr- O (0 t M 0 .92, 4= 03 $ z: 03 92 O O > Q- O > Q. ' i 8. T3 .® -5 w .£. Z w .31, -5 w .0 $, fc_ 03 "o C ® O C ^ Q) C x C) 'o T3 03 "o '03 gj 'E 9> .O £. '3_ .c \J8 e~03 'E - g as '§ Q. c E XI c c ^ ^ E r; M C 55 s .^ 'w S .^ O C UJ '« ffl -B 03 ® 0 2 & I i i E 2 "S ,ic 12 ~o3° i 1 1 CO DC m u. 1- H- > 1- H- > 1- H- > DCJ o Injected 10.50 liters of 20 percent Rhodamine WT dye at 0626 hours on May 1 , 1991 , at river mile 295.33 4 290.34 4.99 4.99 2.42 2.42 2.06 2.83 2.83 1.76 3.27 3.27 1.53 2,813 0.85 5 289.43 .91 5.90 3.57 1.15 .79 4.07 1.24 .73 8.06 4.79 .19 2,825 4.49 47 DYE INJECTED NEAR SKINNER'S FALLS (RIVER MILE 295.4) NUMBER IS SAMPLING SITE 01234567 TIME SINCE INJECTION, IN HOURS Figure 20. Time-concentration curves for the Delaware River at Narrowsburg pool, May 1, 1991. Subsequent to the low-flow study, three stream segments were injected with dye and sampled during reservoir releases. Time-concentration curves were developed for the upstream and downstream sampling points in each segment. Preceding flows were similar to those during the low-flow study. The stream segment between Buckingham Access and Kellams Bridge was sampled following a 12-hour release from Cannonsville Reservoir. The preceding discharge at the streamflow-measurement station at Callicoon, N.Y., was 497 ft3/s. The maximum flow discharge from Cannonsville Reservoir was 1,200 ftVs. The segment between Barryville and Pond Eddy was sampled after a 4-hour release from Lake Wallenpaupack. The preceding discharges at strearnflow-measurement stations at Port Jervis and Montague were 1,530 and 1,670^/8, respectively. The maximum flow discharge from Lake Wallenpaupack was 1,420 ftVs. The segment between Port Jervis and Milford Beach was sampled following a 4-hour release from the Mongaup Reservoir System. The preceding discharges at Port Jervis and Montague were 1,500 and 1,670 ftVs, respectively. The maximum flow discharge from the Mongaup Reservoir System was 720 ft3/s. Each dye injection was timed so that the surge wave passed through the dye cloud between the upstream and downstream sampling sites of each stream segment. Figures 21-23 compare the time-concentration curves developed from data collected during the low-flow and surge- wave studies at Kellam's Bridge, Pond Eddy, and Milford Beach to illustrate the effect of a sudden infusion of water on a contaminant spill. These time-concentration curves were normalized for differences in the volume of dye injected, not for the differences in stream discharge in each study. Less dye was injected for the surge-wave studies, which explains, in part, the reduced peak concentrations during the surge-wave studies. The additional volume of water is another reason for the dilution of the dye resulting in a reduced peak concentration. The most apparent effect of the surge waves on the dye clouds is the decreased traveltime from Buckingham to Kellam's Bridge and from Port Jervis to Milford Beach. The increase in flow results in an increase in the velocity of the water and the dye cloud. The surge wave did not reach Pond Eddy until after sampling had begun, which explains the similar traveltimes of the leading edge for the low-flow and surge-wave study from Barryville. 48 g 0.35 UJ g 0.30 LOW FLOW QC LU SURGE WAVE 0.25 cc a.UJ 0.20 l_^ 8 O 0.15 UJ Q 0.10 LL. O z O § 0.05 h- LL1 O Z o o.oo 10 15 20 25 30 35 40 45 50 55 60 TIME SINCE DYE ARRIVED AT BUCKINGHAM, IN HOURS Figure 21. Time-concentration curves from Kellam's Bridge for the low-flow and surge-wave studies on the Delaware River. 49 S o-30 UJ 0.27 tr UJ LOW FLOW tr 0.24 UJ CL SURGE WAVE £ 0.21 £ 0.18 i § 0,5 O 0.12 UJ" > 0.09 0.06 I 0.03 UJ o z O 0.00 5 10 15 20 25 TIME SINCE DYE ARRIVED AT BARRYVILLE, IN HOURS Figure 22. Time-concentration curves from Pond Eddy for the low-flow and surge-wave studies on the Delaware River. 50 CONCENTRATION OF DYE, IN MICROGRAMS PER LITER PER LITER INJECTED o n 0 (Q 5f c 5 a> 10 0 CO fi?^ 0 o Q. DO 0 o"0 6" 0) Q. (0 c I c 0"Q. (0 O Predicted This report can be used to calculate traveltime by: (1) Use table 1 to determine the river miles in the study reach where the spill was introduced into the river and for the downstream location of concern. (2) Use table 1 to locate the nearest USGS streamflow-measurement station. (3) Determine the discharge at the streamflow-measurement station. Each station can be accessed by phone to determine the current stream gage height. This value can then be applied to a gage height/discharge rating table, created by the USGS, which will provide the corresponding discharge. (4) Use figure 11 to determine the flow duration that most closely corresponds to the discharge at the streamflow-measurement station. (5) Use tables 8-10 or figures 16A-18B to estimate the traveltime (leading edge, peak, and trailing edge) of the spill in that stream segment. When the flow duration is between two of the values provided, interpolate between the values. (6) Use table 11 or figures 19A-19B to determine the duration of the pollutant cloud. This procedure will provide an estimate of when a water-soluble pollutant will reach a site, when the peak concentration will occur, and when the concentration will fall below 10 percent of the peak concentration. It should be repeated for all downstream locations that will be affected by the spill. The user of this report should be aware that an immiscable substance may behave differently than the water-soluble dye used in this study. 52 SUMMARY Traveltime and dispersion studies were made in May and August of 1991 on a 120-mi reach of the Delaware River from the confluence of the East Branch Delaware River and West Branch Delaware River at Hancock, N.Y., to the Delaware Water Gap. This section of the river, most of which is National Park and designated a Scenic and Recreational River, is used extensively for recreation. Introduction of a soluble contaminant could severely effect the water quality. Information on traveltime of water soluble substances is essential for resource managers and health agencies to make informed decisions on a proper response to a spill. Dye was injected at six locations along the river when discharges were at the 85- to 95-percent and 25- to 30-percent flow durations. Time-concentration curves were developed from data collected at 15 sampling locations. These curves were used to determine traveltime of the dye cloud between adjacent sampling points and to determine cumulative traveltimes for the entire reach at 10 flow durations. The data indicate that a spill at Buckingham Access (river mile 325.1) would reach the Delaware Water Gap in about 70 hours when flow was at the 30-percent flow duration. The peak concentration can be expected about 85 hours after the spill occurred at Buckingham Access. Solute concentration would decrease to 10 percent of the peak concentration about 120 hours after introduction of the spill. The Narrowsburg pool and eddy dramatically affect the movement of dye in that section of the river. Prolonged vertical mixing, caused by depths which exceed 100 ft, increases the duration of the dye cloud. A comparison of dye cloud durations at the upstream and downstream end of the pool show an increase of over 50 percent in the time required for passage of the dye cloud at the downstream site. 53 REFERENCES CITED Delaware River Basin Commission, 1988, The Delaware River Basin stream mileage system: Staff Paper 105,110 p. Fischer, H.B., List, E.J., Koh, R.C.Y., Imberger, J., and Brooks, N.H., 1979, Mixing in inland and coastal waters: New York, Academic Press, Inc., 483 p. Hubbard, E.F., Kilpatrick, F.A., Martens, L.A., and Wilson, J.F, Jr., 1982, Measurement of time of travel and dispersion in streams by dye tracing: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. A9,44 p. Kilpatrick, F.A., and Wilson, J.F, Jr., 1989, Measurement of time of travel in streams by dye tracing: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. A9,27 p. Searcy, J.K., 1959, How-duration curves: U.S. Geological Survey Water-Supply Paper 1542-A, 33 p. Thomann, R.V., and Mueller, J.A., 1987, Principles of surface water quality modeling and control: New York, Harper & Row, 644 p. Wilson, J.F., Jr., Cobb, E.D., and Kilpatrick, F.A., 1984, Huorometric procedures for dye tracing: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. A12,34 p. 54